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The Incidence and Surgical Treatment of Carcinoma in Adenomatous Goiter
The Incidence and Surgical Treatment of Carcinoma in Adenomatous Goiter J. WILLIAM HINTON, M.D., F.A.C.S. * LOUIS R. SLATTERY, M.D., F.A.C.S.**
INCIDENCE SURGEONS have long been aware of the occurrence of carcinoma in clinically benign nodular goiters. The role of the adenoma as a precursor of cancer was pointed out by Ehrhardt! in 1902 when he reported 200 cases of cancer of the thyroid with pre-existing adenomas in 104 cases. However, a history of goiter was given in only 21 cases. In 1924 Allen Graham2 reported 65 carcinomas of the thyroid with 92.4 per cent incidence in pre-existing adenomas. Crile 3 has pointed out that no reference is made concerning the presence or absence of pre-existing goiters in these cases. Graham's2 paper made other observations of importance for the understanding of the clinical behavior of thyroid cancer, and the rationale of its surgical treatment. He observed that carcinomas arising in adenomas are encapsulated lesions which metastasize by blood vessel invasion until their capsule has been destroyed, giving access to lymphatic channels and.the remainder of the gland. Except for papers by Pemberton 4 in 1939, and Lahey, Hare and Warren 5 in 1940, which touched upon the relationship between carcinoma and adenomatous goiters, there was little interest in this facet of the cancer problem. Cope 6 has pointed out in his progress report on "Diseases of the Thyroid Gland" that attention was finally focused upon the incidence of cancer in nodular goiter in 1944 and 1945 by the papers of Ward,1 Cole and his co-workers,8 and Hinton and Lord. 9 In 1947 two papers
From the Department of Surgery, N ew York University Post-Graduate Medical School and Fourth Surgical Division (New York University) of Bellevue Hospital, New York City.
* Professor and Chairman of Department of Surgery, New York University PostGraduate Medical School; Director of Surgery, University Hospital and Fourth Surgical Division, Bellevue Hospital. ** Associate Professor of Clinical Surgery, New York University Post-Graduate Medical School; Visiting Surgeon, University Hospital and Bellevue Hospital. 351
352
J. William Hinton, Louis R. Slattery
were published by internists showing a much lower incidence of carcinoma in nodular goiter than reported in the preceding surgical papers. Analysis of these papers has shown that their conclusions are misleading in that the material from which they were drawn was not comparable to that of the surgeons. Vanderlaan'slo observations were based upon autopsy material from three Boston hospitals. Cope 6 points out that this source would not reflect the true incidence of thyroid cancer, as patients with this disease survive hospital procedures and go on to lingering deaths at home should it prove fatal. He objects to the conclusions of Rogers, Asper and Williams,ll as their material included hyperfunctioning nodular goiters as well as nontoxic nodular goiters, thereby diluting the incidence of carcinoma. Pemberton4 and Crile 3 have questioned the accuracy of statistics concerning the origins of carcinomas in pre-existing adenomas. This is based upon their experience with nodules of low grade malignancy which have obviously been carcinomas since their inception. This fact is cited as a matter of pathological interest. Geographical Incidence
Table 1 summarizes the incidence of cancer in nodular goiters reported by surgeons throughout the country. Geographical variation is noted, there being some tendency toward a higher rate in the central portion of the country in comparison to that on each seaboard. The variation within the same city illustrated by the reports from Boston is considered by Cope 12 to be due to different sources of material and the channeling of patients with certain lesions to one institution. The incidence of carcinoma seems to remain remarkably constant over the years as exemplified by the reports of Cole8 • 13 Beahrs 14 and Pemberton. 4 Our own material illustrates this point also, there being a 7.2 per cent incidence of carcinoma in 262 nontoxic nodular goiters operated upon since the report by the senior author and Lord 9 in 1945, when a 7.6 per cent incidence was reported. The majority of authors agree that the single nontoxic nodule or adenoma shows the highest incidence of carcinoma. There is increasing tendency to regard multinodular enlargements with only slightly less suspicion. Beahrs, Pemberton and Black 14 have found it impossible to divide their material into single and multinodular goiters. Their records showed little agreement as to whether nodules were single or multiple among physicians examining patients. The physical findings and pathological reports also disagreed frequently. Cases considered to have single nodules by many examiners were found to have multiple nodules on pathological examination in more instances than not. Examination of our own material corroborates these difficulties. Furthermore, compari-
Carcinoma in Adenomatous Goiter
353
son of clinical findings with operative records showed that many cases considered to have a solitary nodule confined to one lobe, were found to have similar nodules in the opposite lobe at operation. Cerise, Spears and Ochsner 15 summarize this problem stating that we are unable to diagnose thyroid cancer early by present clinical means and the incidence of cancer in single and multinodular nontoxic goiters is high enough to warrant thyroidectomy unless a serious contraindication exists. Crile 3 considers thyroidectomy for nodular goiters a procedure primarily designed to remove existing cancer in suspicious nodules. Table 1 GEOGRAPHICAL INCIDENCE OF CARCINOMA IN NONTOXIC NODULAR GOITER
AUTHOR
YEAR
LOCATION
--
- -
Lahey and Hare5. Cope 12 . . . ..... Anglem and Bradford l " Hinton and Lord 9. Hinton and Slattery. Horn et aI 20 . Cole et alB. Cole et a1 13 . Crile 3. Pemberton 4 . . Beahrs et ap4 .. Young21. ...... Cerise et aP5 .. Ward 7 . . • . . .
1951 1949 1948 1945 1952 1947 1945 1950 1950 1939 1951 1950 1952 1944
PER PER CAR- CENT IN CENT IN CINOMA, MULTI- SINGLE NODU- NODUPER LAR LAR CENT GOITERS GOITER
Boston Boston Boston New York City New York City Philadelphia Chicago Chicago Cleveland Rochester, Minn. Rochester, Minn. Oklahoma New Orleans San Francisco
4.8 10.1 7.6 7.6 7.2 17.2 17.1 10.9 4.9 3.8 9.4 17.3 4.8
0.62 4.8
10.4 19 9
-
-
9.8
-
11
9.8 3.4 -
0.0 12.8 -
-
24 24.4 24.5 -
18.2 19.8 15.6
CLINICAL FEATURES
Comparison of the clinical data reported by various authors shows striking similarity among all. Our own series of 19 carcinomas found in 262 nontoxic nodular goiters removed at operation conforms to the general pattern. Women predominate over men in all series, but Cerise and his associates 15 have pointed out that this is due to nodular goiter being more frequent in women, the incidence of cancer in nodular goiters actually being higher in men. Although most patients were in middle life, carcinoma occurred at both extremes of life, and all authors emphasize the urgency for investigation of thyroid nodules in children. The duration of malignant lesions varied from detection on routine physical examination to existence for decades. Beahrs, Pemberton and Black 14 point out that little can be inferred concerning the possibility of
354
J. William Hinton, Louis R. Slattery
cancer from the duration of the lesion. Similarly, there is no relationship between the size of the lesion and the presence of carcinoma demonstrated in any reports. A history of recent enlargement has likewise proved of little significance. This point is emphasized by the manner in which carcinomas of low grade malignancy remain the same size for years, as reported by Crile. 3 The uniformity of these observations by highly qualified observers attests the lack of criteria to warrant expectant observation of nontoxic nodular goiters. SURGICAL TREATMENT
Graham's2 observations provide our rationale for the removal of solitary nodular goiters. Total excision of the involved lobe and adjacent isthmus should suffice for complete local removal of carcinomas which have not broken through the capsule to invade lymphatics or the remainder of the gland. Such excision should constitute an adequate definitive procedure for the clinically unsuspected lesion discovered in the pathology laboratory.13 The majority of surgeons favor complete lobectomy with removal of the adjacent isthmus. Lahey16 prefers to enucleate the nodule and await the pathological report on the paraffin section. In the event an unsuspected carcinoma is found, removal of the lobe, muscles and radical neck dissection in continuity are performed at a second procedure. This has the theoretical disadvantage of possible seeding of the operative field with cancer cells, and also may leave the surgeon with a difficult decision to make if an equivocal report of malignancy is returned by the pathologist. Although some surgeons rely upon frozen sections, we have found them unreliable, a point also emphasized by Lahey,16 Cope 12 has called attention to the importance of searching for early lymph node metastasis before removal of a clinically benign nodule is begun. He advises searching preoperatively and at operation for the node above the isthmus as a site of early metastasis of carcinomas in the adjacent lobes and has called this node the Delphian node because of its oracular capacity to indicate unsuspected carcinoma in the adjacent lobes. When an enlarged Delphian node is found, removal and frozen section are advised so that radical thyroidectomy and neck dissection may be done immediately without disturbing the primary lesion to establish the diagnosis. The preisthmic node lying in front of the isthmus is a less frequent site of early metastasis but should also be investigated on physical examination and at operation. Inflammatory lesions, .especially Hashimoto's disease, may cause enlargement of these nodes, so that these must be excluded before a radical procedure is undertaken. The operative procedure for removal of multinodular goiters is less
Carcinoma in Adenomatou8 Goiter
355
logical than that for solitary nodules. Although the entire gland is abnormal in most instances, no one advises total thyroidectomy. Subtotal resection leaves abnormal tissue behind. Copel2 questions the rationale of this procedure from the standpoint that the small remnant is subject to hyperplastic stimulation by the increased production of thyroid-stimulating hormone by the anterior pituitary lobe occasioned by the removal
. Thyroid. Vein
'----"VJnf. Thyroid Vein
Fig. 48. A, Incision. B, Mobilization of lobe and exposure of middle thyroid vein.
of thyroid tissue. Crile3 objects to removal of multinodular goiters primarily on a geographical basis applicable to the Great Lakes area, where the high incidence of multiple thyroid nodules in the population makes prophylactic removal economically and physically impossible. The importance of the reciprocal relationship between the thyroid gland and the anterior lobe of the pituitary to the surgeon is illustrated in Cope's12 report of a case of colloid goiter which recurred after two subtotal excisions, finally decreasing to 30 per cent of its former size when sufficient desiccated thyroid was given to maintain a normal basal
J. Willtam Hinton, Louis R. Slattery 356 metabolic rate. Our attention has been similarly directed to this problem by patients whose contralateral lobes have enlarged within a year after hemithyroidectomy. After removal of nontoxic nodular goiters the basal metabolic rate should be followed and if necessary maintained at It normal level with thyroid extract.
Left Upper Pole
Int. Jugular Vein t1ld. Thyroid Vein ~~~:.!#--+-...,...f72:..-
Inf. Thyroid Vein
Fig. 49. Division and ligation of middle thyroid vein and superior thyroid artery and vein.
Technical Considerations
The possibility of carcinoma in the solitary nodule has necessitated changes in the operative technique so that an entire lobe may be removed intact without damage to the recurrent nerves or parathyroids. Manipulation of the gland by hemostats applied near each pole is preferred to sharp hooked instruments so that the capsule may not be ruptured. Exposure of the recurrent nerve and parathyroid glands, an optional step in subtotal resections, is essential if the complete lobe is to be removed without an incidence of nerve injury of about 5 per cent.3 The thyroid gland is exposed (Fig. 48) with or without transverse division of the strap muscles through their upper third. After division of the middle thyroid vein (Fig. 49) the superior thyroid vessels are ligated and the superior pole (Fig. 50) turned down by separation of its medial and posterior fascial attachments to the larynx. With the carotid sheath retracted the inferior thyroid artery is identified (Fig. 50) and traced to
Carcinoma in Adenomatous Goiter
357
Parathyroid dU9ulll.,.
~in
Carotid Artery In!. Thyroid Artery In!. Thyroid Vein
\\
Fig. 50. The superior pole. has been turned down and the inferior thyroid artery isolated and traced to the gland identifying the recurrent nerve.
<-"'1mi<-- Left
Upper Pole
farcdhyroid
Int. duC}ular Vein Carolid Artery In£ Thyroid Art'ery
~lH/L--rlI-Commcn
Fig. 51. The branches of the inferior thyroid artery have been divided preserving the inferior parathyroid and exposing the nerve completely.
358
J. William Hinton, Louis R. Slattery
the gland where its relationship to the recurrent nerve 17 , 18 and parathyroid is established. When the nerve has been identified the artery or its branches are ligated, dropping the nerve posteriorly in its areolar bed (Fig. 51) and permitting its exposure from its point of entry into the operative field inferiorly to its exit superiorly beneath the fibers of the inferior constrictor. Division of the branches of the inferior thyroid artery beneath the lobe permits more certain preservation of the parathyroid in the mass of areolar tissue and fatty lobules in this area.
JRI Thyroid Vein
_ Fig. 52. With the nerve in view the inferior thyroid veins have been divided and the dissection carried medially across the trachea dividing the attachments of the lobe and isthmus.
The nerve and parathyroid remain in full view during the remainder of the procedure as the inferior thyroid veins are divided, exposing the trachea, and the dissection is carried medially and upwards across the trachea, dividing the attachments of the lobe and isthmus to the trachea (Fig. 52) until the entire lobe and isthmus have been removed and the isthmus divided at its junction with the opposite lobe (Fig. 53). This procedure is similar to that of Lahey save for the division of the inferior thyroid artery, and the dissection medially across the trachea in preference to splitting the isthmus, which hides the nerve during much of the actual removal of the lobe. Subtotal resections for multinodular goiters permit preservation of remnants posteriorly to protect the parathyroids and recurrent nerves.
Carcinoma in Adenomatous Goiter
359
However, the technique described permits a more accurate removal of diseased tissue with greater safety for the nerves and parathyroids.
Fig. 53. The completed procedure showing removal of the isthmus beyond the midline.
SUMMARY AND CONCLUSIONS
1. Pathological studies have shown that carcinomas of the thyroid arise in a high percentage of cases from pre-existing adenomas. 2. The highest incidence of carcinoma is in solitary nodules showing no evidence of toxicity. 3. Physical examination of the thyroid gland is so limited in its accuracy that the most experienced examiners cannot be certain whether a thyroid enlargement is a solitary or multinodular process. 4. The incidence of carcinoma in solitary and multinodular goiters is great enough to justify their removal. 5. Solitary nontoxic nodules should be removed by complete lobectomy because of the higher incidence of carcinoma reported in them. 6. Postoperative (')bservation of the basal metabolic rate, with thyroid replacement therapy when indicated, is essential to prevent hyperplasia . of the remaining thyroid tissue. REFERENCES 1. Ehrhardt, 0.: Zur Anatomie u. Klinik der Struma maligna. Beitr. z. klin. ehir. 36: 343, 1902.
360
J. William Hinton, Louis R. Slattery
2. Graham, A.: Malignant Epithelial Tumors of the Thyroid. Surg., Gynec. & Obst. 39: 781, 1924. 3. Crile, George, Jr.: Factors Influencing the Prevention and Cure of Cancer of the Thyroid. Surg., Gynec. & Obst. 91: 210, 1950. 4. Pemberton, J. deJ.: Malignant Lesions of the Thyroid Gland. Surg., Gynec. & Obst. 69: 417, 1939. 5. Lahey, F. H., Hare, H. F. and Warren, S.: Carcinoma of the Thyroid. Ann. Surg. 112: 977, 1940. 6. Cope, 0.: Medical Progress: Diseases of the Thyroid Gland. New England J. Med. 246: 451, 1952. 7. Ward, R.: Malignant Goiter. Surgery 16: 783,1944. 8. Cole, W. H., Slaughter, D. P. and Rossiter, L. J.: Potential Dangers of Nontoxic Nodular Goiters. J.A.M.A. 127: 883, 1945. 9. Hinton, J. W. and Lord, J. W., Jr.: Is Surgery Indicated in All Cases of Nodular Goiter, Toxic and Nontoxic? J.A.M.A. 129: 605, 1945. 10. Vanderlaan, W. P.: The Occurrence of Carcinoma of the Thyroid in Autopsy Material. New England J. Med. 237: 221,1947. 11. Rogers, W. F., Jr., Asper, S. P., Jr. and Williams, R. H.: Clinical Significance of Malignant Neoplasms of the Thyroid Gland. New England J. Med. 237: 569, 1947. 12. Cope, 0., Dobyns, B. M., Hamlin, E. and Hopkirk, J.: What Thyroid Nodules Are to be Feared. J. Clin. Endocrinol. 9: 1012, 1949. 13. Cole, W. H., Slaughter, D. P. and Majarakis, J. D.: Carcinoma of the Thyroid Gland. Surg., Gynec. & Obst. 89: 349, 1949. 14. Beahrs, O. H., Pemberton, J. deJ. and Black, B. M.: Nodular Goiter and Malignant Lesions of the Thyroid Gland. J. Clin. Endocrinol. 11: 1147, 1951. 15. Cerise, E. J., Spears, R. and Ochsner, A.: Carcinoma of the Thyroid and Nontoxic Nodular Goiter. Surgery 16: 783, 1944. 16. Lahey, F. H. and Hare, H. F.: Malignancy in Adenomas of the Thyroid. J.A.M.A. 145: 689, 1951. 17. Armstrong, W. G. and Hinton, J. W.: Multiple Divisions of the Recurrent Laryngeal Nerve. Arch. Surg. 62: 532, 1951. 18. Lahey, F. H. and Hoover, W. B.: Injuries to the Recurrent Laryngeal Nerve in Thyroid Operations. Ann. Surg. 108: 545, 1938. 19. Anglem, T. J. and Bradford, M. L.: Nodular Goiter and Thyroid Cancer. New England J. Med. 239: 217,1948. 20. Horn, R. C. and others: Carcinoma of the Thyroid. Ann. Surg. 126: 140, 1947. 21. Young, M. 0.: Carcinoma of the Thyroid Gland. Surgery 27: 364,1950.
INCIDENCE SURGEONS have long been aware of the occurrence of carcinoma in clinically benign nodular goiters. The role of the adenoma as a precursor of cancer was pointed out by Ehrhardt! in 1902 when he reported 200 cases of cancer of the thyroid with pre-existing adenomas in 104 cases. However, a history of goiter was given in only 21 cases. In 1924 Allen Graham2 reported 65 carcinomas of the thyroid with 92.4 per cent incidence in pre-existing adenomas. Crile 3 has pointed out that no reference is made concerning the presence or absence of pre-existing goiters in these cases. Graham's2 paper made other observations of importance for the understanding of the clinical behavior of thyroid cancer, and the rationale of its surgical treatment. He observed that carcinomas arising in adenomas are encapsulated lesions which metastasize by blood vessel invasion until their capsule has been destroyed, giving access to lymphatic channels and.the remainder of the gland. Except for papers by Pemberton 4 in 1939, and Lahey, Hare and Warren 5 in 1940, which touched upon the relationship between carcinoma and adenomatous goiters, there was little interest in this facet of the cancer problem. Cope 6 has pointed out in his progress report on "Diseases of the Thyroid Gland" that attention was finally focused upon the incidence of cancer in nodular goiter in 1944 and 1945 by the papers of Ward,1 Cole and his co-workers,8 and Hinton and Lord. 9 In 1947 two papers
From the Department of Surgery, N ew York University Post-Graduate Medical School and Fourth Surgical Division (New York University) of Bellevue Hospital, New York City.
* Professor and Chairman of Department of Surgery, New York University PostGraduate Medical School; Director of Surgery, University Hospital and Fourth Surgical Division, Bellevue Hospital. ** Associate Professor of Clinical Surgery, New York University Post-Graduate Medical School; Visiting Surgeon, University Hospital and Bellevue Hospital. 351
352
J. William Hinton, Louis R. Slattery
were published by internists showing a much lower incidence of carcinoma in nodular goiter than reported in the preceding surgical papers. Analysis of these papers has shown that their conclusions are misleading in that the material from which they were drawn was not comparable to that of the surgeons. Vanderlaan'slo observations were based upon autopsy material from three Boston hospitals. Cope 6 points out that this source would not reflect the true incidence of thyroid cancer, as patients with this disease survive hospital procedures and go on to lingering deaths at home should it prove fatal. He objects to the conclusions of Rogers, Asper and Williams,ll as their material included hyperfunctioning nodular goiters as well as nontoxic nodular goiters, thereby diluting the incidence of carcinoma. Pemberton4 and Crile 3 have questioned the accuracy of statistics concerning the origins of carcinomas in pre-existing adenomas. This is based upon their experience with nodules of low grade malignancy which have obviously been carcinomas since their inception. This fact is cited as a matter of pathological interest. Geographical Incidence
Table 1 summarizes the incidence of cancer in nodular goiters reported by surgeons throughout the country. Geographical variation is noted, there being some tendency toward a higher rate in the central portion of the country in comparison to that on each seaboard. The variation within the same city illustrated by the reports from Boston is considered by Cope 12 to be due to different sources of material and the channeling of patients with certain lesions to one institution. The incidence of carcinoma seems to remain remarkably constant over the years as exemplified by the reports of Cole8 • 13 Beahrs 14 and Pemberton. 4 Our own material illustrates this point also, there being a 7.2 per cent incidence of carcinoma in 262 nontoxic nodular goiters operated upon since the report by the senior author and Lord 9 in 1945, when a 7.6 per cent incidence was reported. The majority of authors agree that the single nontoxic nodule or adenoma shows the highest incidence of carcinoma. There is increasing tendency to regard multinodular enlargements with only slightly less suspicion. Beahrs, Pemberton and Black 14 have found it impossible to divide their material into single and multinodular goiters. Their records showed little agreement as to whether nodules were single or multiple among physicians examining patients. The physical findings and pathological reports also disagreed frequently. Cases considered to have single nodules by many examiners were found to have multiple nodules on pathological examination in more instances than not. Examination of our own material corroborates these difficulties. Furthermore, compari-
Carcinoma in Adenomatous Goiter
353
son of clinical findings with operative records showed that many cases considered to have a solitary nodule confined to one lobe, were found to have similar nodules in the opposite lobe at operation. Cerise, Spears and Ochsner 15 summarize this problem stating that we are unable to diagnose thyroid cancer early by present clinical means and the incidence of cancer in single and multinodular nontoxic goiters is high enough to warrant thyroidectomy unless a serious contraindication exists. Crile 3 considers thyroidectomy for nodular goiters a procedure primarily designed to remove existing cancer in suspicious nodules. Table 1 GEOGRAPHICAL INCIDENCE OF CARCINOMA IN NONTOXIC NODULAR GOITER
AUTHOR
YEAR
LOCATION
--
- -
Lahey and Hare5. Cope 12 . . . ..... Anglem and Bradford l " Hinton and Lord 9. Hinton and Slattery. Horn et aI 20 . Cole et alB. Cole et a1 13 . Crile 3. Pemberton 4 . . Beahrs et ap4 .. Young21. ...... Cerise et aP5 .. Ward 7 . . • . . .
1951 1949 1948 1945 1952 1947 1945 1950 1950 1939 1951 1950 1952 1944
PER PER CAR- CENT IN CENT IN CINOMA, MULTI- SINGLE NODU- NODUPER LAR LAR CENT GOITERS GOITER
Boston Boston Boston New York City New York City Philadelphia Chicago Chicago Cleveland Rochester, Minn. Rochester, Minn. Oklahoma New Orleans San Francisco
4.8 10.1 7.6 7.6 7.2 17.2 17.1 10.9 4.9 3.8 9.4 17.3 4.8
0.62 4.8
10.4 19 9
-
-
9.8
-
11
9.8 3.4 -
0.0 12.8 -
-
24 24.4 24.5 -
18.2 19.8 15.6
CLINICAL FEATURES
Comparison of the clinical data reported by various authors shows striking similarity among all. Our own series of 19 carcinomas found in 262 nontoxic nodular goiters removed at operation conforms to the general pattern. Women predominate over men in all series, but Cerise and his associates 15 have pointed out that this is due to nodular goiter being more frequent in women, the incidence of cancer in nodular goiters actually being higher in men. Although most patients were in middle life, carcinoma occurred at both extremes of life, and all authors emphasize the urgency for investigation of thyroid nodules in children. The duration of malignant lesions varied from detection on routine physical examination to existence for decades. Beahrs, Pemberton and Black 14 point out that little can be inferred concerning the possibility of
354
J. William Hinton, Louis R. Slattery
cancer from the duration of the lesion. Similarly, there is no relationship between the size of the lesion and the presence of carcinoma demonstrated in any reports. A history of recent enlargement has likewise proved of little significance. This point is emphasized by the manner in which carcinomas of low grade malignancy remain the same size for years, as reported by Crile. 3 The uniformity of these observations by highly qualified observers attests the lack of criteria to warrant expectant observation of nontoxic nodular goiters. SURGICAL TREATMENT
Graham's2 observations provide our rationale for the removal of solitary nodular goiters. Total excision of the involved lobe and adjacent isthmus should suffice for complete local removal of carcinomas which have not broken through the capsule to invade lymphatics or the remainder of the gland. Such excision should constitute an adequate definitive procedure for the clinically unsuspected lesion discovered in the pathology laboratory.13 The majority of surgeons favor complete lobectomy with removal of the adjacent isthmus. Lahey16 prefers to enucleate the nodule and await the pathological report on the paraffin section. In the event an unsuspected carcinoma is found, removal of the lobe, muscles and radical neck dissection in continuity are performed at a second procedure. This has the theoretical disadvantage of possible seeding of the operative field with cancer cells, and also may leave the surgeon with a difficult decision to make if an equivocal report of malignancy is returned by the pathologist. Although some surgeons rely upon frozen sections, we have found them unreliable, a point also emphasized by Lahey,16 Cope 12 has called attention to the importance of searching for early lymph node metastasis before removal of a clinically benign nodule is begun. He advises searching preoperatively and at operation for the node above the isthmus as a site of early metastasis of carcinomas in the adjacent lobes and has called this node the Delphian node because of its oracular capacity to indicate unsuspected carcinoma in the adjacent lobes. When an enlarged Delphian node is found, removal and frozen section are advised so that radical thyroidectomy and neck dissection may be done immediately without disturbing the primary lesion to establish the diagnosis. The preisthmic node lying in front of the isthmus is a less frequent site of early metastasis but should also be investigated on physical examination and at operation. Inflammatory lesions, .especially Hashimoto's disease, may cause enlargement of these nodes, so that these must be excluded before a radical procedure is undertaken. The operative procedure for removal of multinodular goiters is less
Carcinoma in Adenomatou8 Goiter
355
logical than that for solitary nodules. Although the entire gland is abnormal in most instances, no one advises total thyroidectomy. Subtotal resection leaves abnormal tissue behind. Copel2 questions the rationale of this procedure from the standpoint that the small remnant is subject to hyperplastic stimulation by the increased production of thyroid-stimulating hormone by the anterior pituitary lobe occasioned by the removal
. Thyroid. Vein
'----"VJnf. Thyroid Vein
Fig. 48. A, Incision. B, Mobilization of lobe and exposure of middle thyroid vein.
of thyroid tissue. Crile3 objects to removal of multinodular goiters primarily on a geographical basis applicable to the Great Lakes area, where the high incidence of multiple thyroid nodules in the population makes prophylactic removal economically and physically impossible. The importance of the reciprocal relationship between the thyroid gland and the anterior lobe of the pituitary to the surgeon is illustrated in Cope's12 report of a case of colloid goiter which recurred after two subtotal excisions, finally decreasing to 30 per cent of its former size when sufficient desiccated thyroid was given to maintain a normal basal
J. Willtam Hinton, Louis R. Slattery 356 metabolic rate. Our attention has been similarly directed to this problem by patients whose contralateral lobes have enlarged within a year after hemithyroidectomy. After removal of nontoxic nodular goiters the basal metabolic rate should be followed and if necessary maintained at It normal level with thyroid extract.
Left Upper Pole
Int. Jugular Vein t1ld. Thyroid Vein ~~~:.!#--+-...,...f72:..-
Inf. Thyroid Vein
Fig. 49. Division and ligation of middle thyroid vein and superior thyroid artery and vein.
Technical Considerations
The possibility of carcinoma in the solitary nodule has necessitated changes in the operative technique so that an entire lobe may be removed intact without damage to the recurrent nerves or parathyroids. Manipulation of the gland by hemostats applied near each pole is preferred to sharp hooked instruments so that the capsule may not be ruptured. Exposure of the recurrent nerve and parathyroid glands, an optional step in subtotal resections, is essential if the complete lobe is to be removed without an incidence of nerve injury of about 5 per cent.3 The thyroid gland is exposed (Fig. 48) with or without transverse division of the strap muscles through their upper third. After division of the middle thyroid vein (Fig. 49) the superior thyroid vessels are ligated and the superior pole (Fig. 50) turned down by separation of its medial and posterior fascial attachments to the larynx. With the carotid sheath retracted the inferior thyroid artery is identified (Fig. 50) and traced to
Carcinoma in Adenomatous Goiter
357
Parathyroid dU9ulll.,.
~in
Carotid Artery In!. Thyroid Artery In!. Thyroid Vein
\\
Fig. 50. The superior pole. has been turned down and the inferior thyroid artery isolated and traced to the gland identifying the recurrent nerve.
<-"'1mi<-- Left
Upper Pole
farcdhyroid
Int. duC}ular Vein Carolid Artery In£ Thyroid Art'ery
~lH/L--rlI-Commcn
Fig. 51. The branches of the inferior thyroid artery have been divided preserving the inferior parathyroid and exposing the nerve completely.
358
J. William Hinton, Louis R. Slattery
the gland where its relationship to the recurrent nerve 17 , 18 and parathyroid is established. When the nerve has been identified the artery or its branches are ligated, dropping the nerve posteriorly in its areolar bed (Fig. 51) and permitting its exposure from its point of entry into the operative field inferiorly to its exit superiorly beneath the fibers of the inferior constrictor. Division of the branches of the inferior thyroid artery beneath the lobe permits more certain preservation of the parathyroid in the mass of areolar tissue and fatty lobules in this area.
JRI Thyroid Vein
_ Fig. 52. With the nerve in view the inferior thyroid veins have been divided and the dissection carried medially across the trachea dividing the attachments of the lobe and isthmus.
The nerve and parathyroid remain in full view during the remainder of the procedure as the inferior thyroid veins are divided, exposing the trachea, and the dissection is carried medially and upwards across the trachea, dividing the attachments of the lobe and isthmus to the trachea (Fig. 52) until the entire lobe and isthmus have been removed and the isthmus divided at its junction with the opposite lobe (Fig. 53). This procedure is similar to that of Lahey save for the division of the inferior thyroid artery, and the dissection medially across the trachea in preference to splitting the isthmus, which hides the nerve during much of the actual removal of the lobe. Subtotal resections for multinodular goiters permit preservation of remnants posteriorly to protect the parathyroids and recurrent nerves.
Carcinoma in Adenomatous Goiter
359
However, the technique described permits a more accurate removal of diseased tissue with greater safety for the nerves and parathyroids.
Fig. 53. The completed procedure showing removal of the isthmus beyond the midline.
SUMMARY AND CONCLUSIONS
1. Pathological studies have shown that carcinomas of the thyroid arise in a high percentage of cases from pre-existing adenomas. 2. The highest incidence of carcinoma is in solitary nodules showing no evidence of toxicity. 3. Physical examination of the thyroid gland is so limited in its accuracy that the most experienced examiners cannot be certain whether a thyroid enlargement is a solitary or multinodular process. 4. The incidence of carcinoma in solitary and multinodular goiters is great enough to justify their removal. 5. Solitary nontoxic nodules should be removed by complete lobectomy because of the higher incidence of carcinoma reported in them. 6. Postoperative (')bservation of the basal metabolic rate, with thyroid replacement therapy when indicated, is essential to prevent hyperplasia . of the remaining thyroid tissue. REFERENCES 1. Ehrhardt, 0.: Zur Anatomie u. Klinik der Struma maligna. Beitr. z. klin. ehir. 36: 343, 1902.
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J. William Hinton, Louis R. Slattery
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