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The treatment of malignant tumours of the maxillary antrum
Clinical Radiology (1986) 37, 179-182 © 1986 Royal College of Radiologists
0009-9260/86/578179502.00
The Treatment of Malignant Tumours of the Maxillary Antrum* T. W. B A C K H O U S E
Department of Radiotherapy and Oncology, Coventry and WarwickshireHospital, Coventry The problems involved in the treatment of malignant tumours of the maxillary antrum are described and the need for a disciplined approach emphasised. The overall crude 5-year survival rate for this series of 43 cases was 49 %. For the 34 patients suffering from carcinoma the rate was 44%. It is suggested that primary surgery be avoided because in the 23 cases treated by radiotherapy before major surgery the 5-year crude survival rate was 60.8%.
sometimes it is tempting to believe that computed tomographic scans provide precise definition of the volume requiring treatment, and modern supervoltage therapy beams have little penumbra to compensate for tidiness in planning treatment of the visible lesion alone. A patient with an antral carcinoma in which there is absolutely no evidence of spread through the orbital floor may eventually develop tumour in the orbit. RADIOTHERAPY
The radiotherapy of tumours of the maxillary antrum presents one of the greatest challenges to the ingenuity of the therapist. The advent of supervoltage radiation has done little to make the task easier to accomplish well. The anatomy of the nose and its associated sinuses causes problems for the radiotherapist, due not only to the irregular shape of the nose but also to the nongeometrical arrangement of the antra, ethmoids, frontal sinuses and sphenoidal sinus, which vary in size and shape from one person to the next. The proximity of the eye, the pituitary and the base of brain to the air passages has to be very carefully taken into account. However, these facts should not be regarded as excuses for failure to cure such cases. The diagnosis of carcinoma of the upper respiratory tract is most commonly made by an ear, nose and throat surgeon, although an unexplained enlarged lymph node in the neck may be removed by a general surgeon. For the radiotherapist, two vital pieces of information can be obtained by the surgeon - the histology and the macroscopic extent of the lesion. The further less obvious extent of the lesion may be demonstrated by diagnostic radiology including computed tomography. The extent of the lesion can only be determined by a thorough clinical examination, suitable investigations, and knowledge of the nature of the pathology and anatomy of the area. Figure 1 illustrates the bony relationships of the orbit to the ethmoids and antrum, and the antrum to the pterygoid fossa. It is easy to see how a medial growth may enter the nose and the medial portion of the orbit (Fig. la, b), how a posterior growth can penetrate into the pterygoid fossa (Fig. lb, c), and how an inferior growth can involve the palate (Fig. 2a). Clinical examination may reveal a swelling of the cheek, a loss of sensation on the cheek due to involvement of the infraorbital nerve, excessive mucoid nasal discharge, visible growth in the mouth or the nose, displacement of the globe within the orbit or proptosis. The distinction between the macroscopic lesion and the true extent of the tumour needs emphasis, because *Based on a paper delivered at the Royal College of Radiologists Provincial Meeting in Coventry 1984.
The maxillary antrum is the most accessible of the sinuses, and the most commonly affected by neoplasia. Precision in defining the volume to be given a high dose of radiation requires precision in positioning the beams. Most centres now have facilities for the production of well-fitting beam-direction shells. Immobilisation of the patient is essential for accurate beam direction, and planning can proceed on the plaster cast with the cooperation between physicist and therapist which characterises a disciplined department. Entrance and exit points for the various beams can be decided with a high degree of accuracy, and the setting up of the treatment is facilitated. Dosage schedules vary from centre to centre, but 60 Gy must be given to the whole target volume in 30 fractions over 6 weeks at 4 MeV, or the equivalent. Infection is almost always present, and adequate drainage of the antral cavity should be ensured during the treatment. The eye, if included in the fields, must be examined regularly as a bacterial conjunctivitis often accompanies the reaction produced by the radiotherapy. Mouth hygiene, ophthalmic care and general support of the patient are all very important throughout the therapy course. The antrum may well have been surgically drained before the patient is referred for radiotherapy, but Fig. 2a illustrates a case where the growth had already penetrated the hard palate when the patient presented. Shrinkage of this growth assured drainage and Fig. 2a shows the defect left many years later. The patient declined a full palatal antrostomy and this defect was all that was available for subsequent inspection of the cavity. The cosmetic result of radiotherapy was satisfactory (Fig. 2b). Normally a palatal antrostomy is performed when the radiation reaction has subsided, usually some 4-6 weeks after completion of treatment. This gives the surgeon the opportunity to assess the result of the radiotherapy, to biopsy any suspicious areas, and to use diathermy on any obvious residual growth. A temporary obturator, and later an obturator attached to a dental plate, closes the defect in the palate. Subsequent inspection of the cavity is easy. Figure 3a illustrates the palatal antrostomy and Fig. 3b shows the external appearances several years after treatment. Some crusting in the antral cavity seems to be inevitable and this should be removed to examine the
180
CLINICAL RADIOLOGY
v
j v
~v
(c) j~ 5
Fig. 1 - Bony relationships of the orbit to the ethmoids and antrum, and the antrum to the pterygoid fossa. (a) The medial wall and floor of the orbit. (b) The floor of the orbit and proximity of the nasal cavity to the antrum. (c) The palate and the pterygoid fossa.
PROBLEMS AND POSSIBLE CAUSES OF FAILURE
vv3
(b)
mucosa at the follow-up clinic. Only if it becomes offensive does a patient need to irrigate the cavity. There is now a belief that primary surgery should be undertaken, and radiotherapy used to 'mop-up' what the surgeon might have left. However, primary maxillectomy postpones the start of radiotherapy. The patient often has difficulty in eating due to the temporary dental plate. Veins and lymphatics in the periphery of the tumour may have been opened and may well lead to dissemination of tumour to areas outside the original tumour volume. Bone necrosis following the radiotherapy is more likely, due to the inevitable exposure and possible infection of bone at operation. The subsequent sequestration may be a long and painful process.
Clinical examination, surgical exploration and radiology are all essential in determining the extent of the tumour, but a knowledge of the likely method and manner of spread also is vital. Our experience is limited, but spread to distant sites has not been a feature of the cases we have treated. The problem has been local spread. Spread to the pterygoid fossa, to the orbit, and to the ethmoids must be very seriously considered despite negative radiological, clinical or surgical findings. It is rare to see patients presenting with cervical lymphadenopathy who are subsequently shown to have an antral carcinoma. This contrasts sharply with other malignancies in this region such as those of the nasopharynx, oral cavity or pharynx. Figure 4 illustrates the exception. This patient presented with a carcinoma of the antrum which was treated as usual, but some months later an enlarged upper deep cervical node developed. A formal block dissection was performed and the presence of metastatic carcinoma confirmed. The patient is alive and well 10 years later. Only the earliest cancers of the antero-lateral wall or the floor of the antrum can be expected not to have penetrated to the pterygoid fossa, or into the orbit. Even so, undifferentiated or poorly differentiated carcinomas may well extend far beyond their macroscopic limits. Therefore, when there is any doubt at all, if the tumour is not confined to the floor or antero-lateral wall and is not well differentiated, it is wrong to omit the pterygoid
MALIGNANT TUMOURS OF THE MAXILLARY ANTRUM
181
(a) Fig. 2 - Case 1. (a) The effect, after many years, of a growth which penetrated the palate. (b) The cosmetic result of treatment. area and the orbit from the volume of irradiation. If the evidence suggests that the medial wall of the antrum is involved then one should expect to see the tumour within the nasal cavity and ethmoids, and the volume to be irradiated must extend to the nasal septum. Growth penetrating the lateral wall of the nose can sometimes spread onto the nasal septum. The superior extent of the treated volume would normally extend up to the level of the eyebrow and only if the t u m o u r is obviously in the frontal sinuses would one include the ipsilateral frontal sinus. The causes for failure are: (1) Failure to extend the treatment volume to enclose the growth completely. (2) Failure to appreciate the poorly differentiated nature of the growth as a result of an inadequate, unrepresentative biopsy. (3) Failure to achieve a cancerocidal dose tO the whole of the tumour-bearing volume.
(a) Fig. 3 - Case 2. (a) The palatal antrostomy aperture. (b) The excellent cosmetic result after treatment. 16
(b) (4) Resistance of the growth to the lethality of radiation due to: (a) concurrent infection in bone, (b) poor blood supply and anoxia which may be the result of the size of the tumour, (c) inherent radio-resistance of the tumour.
(b)
182
CLINICAL RADIOLOGY Table 2 - Five-year survival in relation to t u m o u r histology
Histological type
No.
Crude 5-year survival
%
Squamousce2!} 1!/ 471
Adenocarcinoma Anaplastic Mixed adenocarcinoma and squamous cell Transitional Adenoid cystic Histiocytosis X Lymphoma Unknown Myxofibrosarcoma Total
66 4
34
15
2 1 1 4 1
2 0 1 2 1
43
21
44%
100 1 100 0 100 50 100 49
Table 3 - Five-year survival rate in relation to time of surgery
Time of surgery
No.
Crude 5-year survival
%
Before radiotherapy After radiotherapy
3 23
1 14
33 60.8
Table 4 - Details of histology and 5-year survival rates in patients receiving surgery after radiotherapy
Surgery after radiotherapy
Fig. 4 - Case 3. This patient presented with carcinoma of the antrum. Appearance 10 years after radiotherapy, maxillectomy and right-sided block dissection of the neck.
Attempts elsewhere to use chemotherapy as a precursor to radiotherapy have not produced better results, even when intra-arterial methods have been employed to concentrate the cytotoxic agents within the tumour area. RESULTS OF T R E A T M E N T
Between 1960 and 1978 43 cases of malignancy of the maxillary antrum were treated with radiotherapy. As more modern apparatus became available the treatment changed, but the criteria outlined above were adhered to. Table 1 gives the patient numbers and survival in relation to the apparatus used. With an age range of 1996 years and a wide variation in pathology (Table 2), it is not surprising that death occurred within I year in most fatal cases. Ten patients died in the first year, five in the second, four in the third and three in the fourth year Table 1 - Results of treatment in relation to the apparatus used
Apparatus 250 kV 6°Co 4 Mev
No. of cases
5-year survival (Crude) No.
%
9 23 11
5 10 6
55.5 43.5 54.5
43
21
49
No.
Planned 13 Salvage for local 2 recurrence Salvage for 6 persistent growth Planned, with later 2 salvage Total
23
Histology Positive Negative
5-year survival No. %
7 2
6 0
7 2
53.8 100
6
0
3
50
2
0
2
100
17
6
14
60.8
after treatment - a total of 22 of the 43 cases. In only three cases was surgery performed before radiotherapy, other than for biopsy and drainage, whereas 23 cases were subjected to major surgery after radiotherapy. This had a considerable influence on survival (Table 3). Details of the post-radiation surgery and survival are given in Table 4. No conclusions can be drawn from such small numbers but the 5-year survival figures, totally uncorrected, suggest that attention to detail has proved beneficial and that surgery after radiotherapy is the best approach. This was part of the planned procedure in 15 of the 23 patients so treated. One patient with an adenoid cystic carcinoma required surgery for a local recurrence 12 years after post-radiotherapy surgery and one patient with a squamous carcinoma developed a local recurrence 9 years after initial treatment. Salvage surgery was performed after an interval greater than 6 months from the end of radiotherapy in a further seven patients, one with a local recurrence and six with persistent growth in the cavity. The total crude survival rate at 5 years was 60.8%. Acknowledgements. It is a pleasure to acknowledge the cooperation of the surgeons, physicists and mould-room technicians, and the radiographers who so meticulously carried out the treatments.
0009-9260/86/578179502.00
The Treatment of Malignant Tumours of the Maxillary Antrum* T. W. B A C K H O U S E
Department of Radiotherapy and Oncology, Coventry and WarwickshireHospital, Coventry The problems involved in the treatment of malignant tumours of the maxillary antrum are described and the need for a disciplined approach emphasised. The overall crude 5-year survival rate for this series of 43 cases was 49 %. For the 34 patients suffering from carcinoma the rate was 44%. It is suggested that primary surgery be avoided because in the 23 cases treated by radiotherapy before major surgery the 5-year crude survival rate was 60.8%.
sometimes it is tempting to believe that computed tomographic scans provide precise definition of the volume requiring treatment, and modern supervoltage therapy beams have little penumbra to compensate for tidiness in planning treatment of the visible lesion alone. A patient with an antral carcinoma in which there is absolutely no evidence of spread through the orbital floor may eventually develop tumour in the orbit. RADIOTHERAPY
The radiotherapy of tumours of the maxillary antrum presents one of the greatest challenges to the ingenuity of the therapist. The advent of supervoltage radiation has done little to make the task easier to accomplish well. The anatomy of the nose and its associated sinuses causes problems for the radiotherapist, due not only to the irregular shape of the nose but also to the nongeometrical arrangement of the antra, ethmoids, frontal sinuses and sphenoidal sinus, which vary in size and shape from one person to the next. The proximity of the eye, the pituitary and the base of brain to the air passages has to be very carefully taken into account. However, these facts should not be regarded as excuses for failure to cure such cases. The diagnosis of carcinoma of the upper respiratory tract is most commonly made by an ear, nose and throat surgeon, although an unexplained enlarged lymph node in the neck may be removed by a general surgeon. For the radiotherapist, two vital pieces of information can be obtained by the surgeon - the histology and the macroscopic extent of the lesion. The further less obvious extent of the lesion may be demonstrated by diagnostic radiology including computed tomography. The extent of the lesion can only be determined by a thorough clinical examination, suitable investigations, and knowledge of the nature of the pathology and anatomy of the area. Figure 1 illustrates the bony relationships of the orbit to the ethmoids and antrum, and the antrum to the pterygoid fossa. It is easy to see how a medial growth may enter the nose and the medial portion of the orbit (Fig. la, b), how a posterior growth can penetrate into the pterygoid fossa (Fig. lb, c), and how an inferior growth can involve the palate (Fig. 2a). Clinical examination may reveal a swelling of the cheek, a loss of sensation on the cheek due to involvement of the infraorbital nerve, excessive mucoid nasal discharge, visible growth in the mouth or the nose, displacement of the globe within the orbit or proptosis. The distinction between the macroscopic lesion and the true extent of the tumour needs emphasis, because *Based on a paper delivered at the Royal College of Radiologists Provincial Meeting in Coventry 1984.
The maxillary antrum is the most accessible of the sinuses, and the most commonly affected by neoplasia. Precision in defining the volume to be given a high dose of radiation requires precision in positioning the beams. Most centres now have facilities for the production of well-fitting beam-direction shells. Immobilisation of the patient is essential for accurate beam direction, and planning can proceed on the plaster cast with the cooperation between physicist and therapist which characterises a disciplined department. Entrance and exit points for the various beams can be decided with a high degree of accuracy, and the setting up of the treatment is facilitated. Dosage schedules vary from centre to centre, but 60 Gy must be given to the whole target volume in 30 fractions over 6 weeks at 4 MeV, or the equivalent. Infection is almost always present, and adequate drainage of the antral cavity should be ensured during the treatment. The eye, if included in the fields, must be examined regularly as a bacterial conjunctivitis often accompanies the reaction produced by the radiotherapy. Mouth hygiene, ophthalmic care and general support of the patient are all very important throughout the therapy course. The antrum may well have been surgically drained before the patient is referred for radiotherapy, but Fig. 2a illustrates a case where the growth had already penetrated the hard palate when the patient presented. Shrinkage of this growth assured drainage and Fig. 2a shows the defect left many years later. The patient declined a full palatal antrostomy and this defect was all that was available for subsequent inspection of the cavity. The cosmetic result of radiotherapy was satisfactory (Fig. 2b). Normally a palatal antrostomy is performed when the radiation reaction has subsided, usually some 4-6 weeks after completion of treatment. This gives the surgeon the opportunity to assess the result of the radiotherapy, to biopsy any suspicious areas, and to use diathermy on any obvious residual growth. A temporary obturator, and later an obturator attached to a dental plate, closes the defect in the palate. Subsequent inspection of the cavity is easy. Figure 3a illustrates the palatal antrostomy and Fig. 3b shows the external appearances several years after treatment. Some crusting in the antral cavity seems to be inevitable and this should be removed to examine the
180
CLINICAL RADIOLOGY
v
j v
~v
(c) j~ 5
Fig. 1 - Bony relationships of the orbit to the ethmoids and antrum, and the antrum to the pterygoid fossa. (a) The medial wall and floor of the orbit. (b) The floor of the orbit and proximity of the nasal cavity to the antrum. (c) The palate and the pterygoid fossa.
PROBLEMS AND POSSIBLE CAUSES OF FAILURE
vv3
(b)
mucosa at the follow-up clinic. Only if it becomes offensive does a patient need to irrigate the cavity. There is now a belief that primary surgery should be undertaken, and radiotherapy used to 'mop-up' what the surgeon might have left. However, primary maxillectomy postpones the start of radiotherapy. The patient often has difficulty in eating due to the temporary dental plate. Veins and lymphatics in the periphery of the tumour may have been opened and may well lead to dissemination of tumour to areas outside the original tumour volume. Bone necrosis following the radiotherapy is more likely, due to the inevitable exposure and possible infection of bone at operation. The subsequent sequestration may be a long and painful process.
Clinical examination, surgical exploration and radiology are all essential in determining the extent of the tumour, but a knowledge of the likely method and manner of spread also is vital. Our experience is limited, but spread to distant sites has not been a feature of the cases we have treated. The problem has been local spread. Spread to the pterygoid fossa, to the orbit, and to the ethmoids must be very seriously considered despite negative radiological, clinical or surgical findings. It is rare to see patients presenting with cervical lymphadenopathy who are subsequently shown to have an antral carcinoma. This contrasts sharply with other malignancies in this region such as those of the nasopharynx, oral cavity or pharynx. Figure 4 illustrates the exception. This patient presented with a carcinoma of the antrum which was treated as usual, but some months later an enlarged upper deep cervical node developed. A formal block dissection was performed and the presence of metastatic carcinoma confirmed. The patient is alive and well 10 years later. Only the earliest cancers of the antero-lateral wall or the floor of the antrum can be expected not to have penetrated to the pterygoid fossa, or into the orbit. Even so, undifferentiated or poorly differentiated carcinomas may well extend far beyond their macroscopic limits. Therefore, when there is any doubt at all, if the tumour is not confined to the floor or antero-lateral wall and is not well differentiated, it is wrong to omit the pterygoid
MALIGNANT TUMOURS OF THE MAXILLARY ANTRUM
181
(a) Fig. 2 - Case 1. (a) The effect, after many years, of a growth which penetrated the palate. (b) The cosmetic result of treatment. area and the orbit from the volume of irradiation. If the evidence suggests that the medial wall of the antrum is involved then one should expect to see the tumour within the nasal cavity and ethmoids, and the volume to be irradiated must extend to the nasal septum. Growth penetrating the lateral wall of the nose can sometimes spread onto the nasal septum. The superior extent of the treated volume would normally extend up to the level of the eyebrow and only if the t u m o u r is obviously in the frontal sinuses would one include the ipsilateral frontal sinus. The causes for failure are: (1) Failure to extend the treatment volume to enclose the growth completely. (2) Failure to appreciate the poorly differentiated nature of the growth as a result of an inadequate, unrepresentative biopsy. (3) Failure to achieve a cancerocidal dose tO the whole of the tumour-bearing volume.
(a) Fig. 3 - Case 2. (a) The palatal antrostomy aperture. (b) The excellent cosmetic result after treatment. 16
(b) (4) Resistance of the growth to the lethality of radiation due to: (a) concurrent infection in bone, (b) poor blood supply and anoxia which may be the result of the size of the tumour, (c) inherent radio-resistance of the tumour.
(b)
182
CLINICAL RADIOLOGY Table 2 - Five-year survival in relation to t u m o u r histology
Histological type
No.
Crude 5-year survival
%
Squamousce2!} 1!/ 471
Adenocarcinoma Anaplastic Mixed adenocarcinoma and squamous cell Transitional Adenoid cystic Histiocytosis X Lymphoma Unknown Myxofibrosarcoma Total
66 4
34
15
2 1 1 4 1
2 0 1 2 1
43
21
44%
100 1 100 0 100 50 100 49
Table 3 - Five-year survival rate in relation to time of surgery
Time of surgery
No.
Crude 5-year survival
%
Before radiotherapy After radiotherapy
3 23
1 14
33 60.8
Table 4 - Details of histology and 5-year survival rates in patients receiving surgery after radiotherapy
Surgery after radiotherapy
Fig. 4 - Case 3. This patient presented with carcinoma of the antrum. Appearance 10 years after radiotherapy, maxillectomy and right-sided block dissection of the neck.
Attempts elsewhere to use chemotherapy as a precursor to radiotherapy have not produced better results, even when intra-arterial methods have been employed to concentrate the cytotoxic agents within the tumour area. RESULTS OF T R E A T M E N T
Between 1960 and 1978 43 cases of malignancy of the maxillary antrum were treated with radiotherapy. As more modern apparatus became available the treatment changed, but the criteria outlined above were adhered to. Table 1 gives the patient numbers and survival in relation to the apparatus used. With an age range of 1996 years and a wide variation in pathology (Table 2), it is not surprising that death occurred within I year in most fatal cases. Ten patients died in the first year, five in the second, four in the third and three in the fourth year Table 1 - Results of treatment in relation to the apparatus used
Apparatus 250 kV 6°Co 4 Mev
No. of cases
5-year survival (Crude) No.
%
9 23 11
5 10 6
55.5 43.5 54.5
43
21
49
No.
Planned 13 Salvage for local 2 recurrence Salvage for 6 persistent growth Planned, with later 2 salvage Total
23
Histology Positive Negative
5-year survival No. %
7 2
6 0
7 2
53.8 100
6
0
3
50
2
0
2
100
17
6
14
60.8
after treatment - a total of 22 of the 43 cases. In only three cases was surgery performed before radiotherapy, other than for biopsy and drainage, whereas 23 cases were subjected to major surgery after radiotherapy. This had a considerable influence on survival (Table 3). Details of the post-radiation surgery and survival are given in Table 4. No conclusions can be drawn from such small numbers but the 5-year survival figures, totally uncorrected, suggest that attention to detail has proved beneficial and that surgery after radiotherapy is the best approach. This was part of the planned procedure in 15 of the 23 patients so treated. One patient with an adenoid cystic carcinoma required surgery for a local recurrence 12 years after post-radiotherapy surgery and one patient with a squamous carcinoma developed a local recurrence 9 years after initial treatment. Salvage surgery was performed after an interval greater than 6 months from the end of radiotherapy in a further seven patients, one with a local recurrence and six with persistent growth in the cavity. The total crude survival rate at 5 years was 60.8%. Acknowledgements. It is a pleasure to acknowledge the cooperation of the surgeons, physicists and mould-room technicians, and the radiographers who so meticulously carried out the treatments.