Cancer of the breast - Primary irradiation

Proceedingsofthe32ndAnnualASTRO

Meeting

99

205 PRACTICAL

TOPOGRAPHIC

Guy J.F. Juillard, Department

ANATOMY

FOR RADIATION

THERAPY

M.D.

of Radiation

Oncology,

A number of reliable presented and discussed.

UCLA Center

anatomic

for Health

landmarks

that

are

Science, of

Los Angeles,

interest

to

the

CA

90024

radiation

oncologist

will

be

The knowledge of these landmarks can save time and overcome the need to obtain radiographs during treatment planning, and external landmarks are most helpful for clinical set-ups in emergency radiation therapy situations that often occur after hours when minimal technical help is available. Particular attention will be given to the head and neck area and its variety of custom shaped fields, and the treatment of breast cancer and Hodgkin's disease with emphasis on projection of lymph nodes. In addition, a rapid review of the anatomy of other areas of the body will be addressed. Discussion

will follow,

and participants

will have an opportunity

to share their experience.

206 CAUSES

OF FAILURE

IN THE RADIATION

THERAPY

Lester

J. Peters,

M.D. and Gilbert

H. Fletcher,

Division

of Radiotherapy,

The University

OF HEAD AND NECK CANCER M.D.

of Texas

M.D. Anderson

Cancer

Center,

Houston,

Texas

77030

Review of potential causes of failure of radiotherapy for head and neck cancers provides a framework and technical factors determining for discussion of a variety of tumor-related, host-related, radiocurability. This refresher course will consist of a review of theoretical concepts and experimental data (supported by illustrative examples from everyday clinical practice) underlying the following inherent cellular radioresistance, volume of cancer, tumor cell hypoxia, potential causes of failure: tumor cell regeneration, failure of redistribution, delayed tumor regression, radiation dose and fraction size, shape of dose response curve, geographical miss or underdosage, and second primary tumors occurring Emphasis will be place on causes of failure that can be minimized by in the irradiated volume. application of concepts and techniques readily available to all radiotherapists? and on those that provide the hasis of new treatment strategies based on the radiobiological characteristics of individual tumors.

207 CANCER Barbara

OF THE BREAST L. Fowble,

- PRIMARY

IRRADIATION

M.D. and Robert

Departments of Radiation Therapy, Center, Philadelphia, Pennsylvania

L. Goodman, University 19104

M.D. of Pennsylvania

School

of Medicine

and The Fox Chase

Cancer

In the last 10 years both prospective randomized clinical trials and retrospective series have established the role of conservative surgery and radiotherapy as an alternative to mastectomy in the treatment of early breast cancer. This presentation will review the available data from these studies. Points of discussion will include the role of patient selection (patient age, tumor size and nodal status, histology and mammographic findings), the extent of the surgical procedure in the breast (incisional versus excisional biopsy, wide excision versus quadrantectomy), the role of re-excision, the assessment of surgical margins and their significance, the role and extent of the axillary staging procedure, the extent of radiotherapy (breast versus breast and regional node irradiation), and the role of the boost. Each of these issues will be addressed and current treatment policies and recommendations will be outlined. Local The ability to combine adjuvant recurrence rates and predictors of breast recurrence will be discussed. chemotherapy with primary radiotherapy for patients with histologically positive axillary nodes will be reviewed in terms of selection and sequencing of agents, the ability to deliver optimal doses of chemotherapy and the effect of chemotherapy on cosmesis and complications. Long term effects of radiation therapy will be discussed including the incidence of contralateral breast cancer and second malignancy. Mammographic changes post radiation will be presented. Future and ongoing trials will be reviewed including a renewed interest in the omission of breast irradiation in selected patients after wide excision only. Data relevant to this approach will be presented. Finally, the role of conservative surgery and radiotherapy in the treatment of non-invasive intraductal breast cancer will be presented.