The major objective for surgery of the primary cancer is to achieve optimal local control of the lesion. Local control is defined as the elimination of the neoplastic process and establishing a milieu in which local tumor recurrence is minimized. Historically, this was achieved with radical extirpative surgeries that shaped the surgical oncologists' major objective, namely, avoiding a local recurrence. Before William Halsted's description of the radical mastectomy, surgical treatment of breast cancer resulted in a dismal local control rate of less than 30%. The reason why Halsted's procedure was adopted as a standard approach was because he achieved greater than 90% local control, despite the fact that the overall survival of his patients was not improved.4 The latter was due to the locally advanced stage of the patients who were treated in those days. This consideration ushered in the concept of en bloc removal of adjacent tissue when removing a primary cancer. Halsted's mastectomy involved the removal of adjacent skin (often necessitating a skin graft), underlying pectoral muscles, and axillary lymph nodes (Figure 4.1).
One of the major principles of surgical therapy of the primary tumor is to obtain adequate negative margins around the primary tumor, which could mean different operative approaches depending on the tumor type and its local involvement with adjacent structures. For example, the removal of a primary colon cancer that involves an adjacent loop of small bowel or bladder requires the en bloc resection of the primary tumor along with removal of the involved segment of small bowel and bladder wall. This approach avoids violation of the primary tumor margins that could lead to tumor spillage and possible implantation of malignant cells in the surrounding normal tissues. Aside from biopsies of the primary tumor, the lesion should not be entered during a definitive resection. In fact, any biopsy tract or incision that was performed before the tumor resection should be included in the procedure to reduce the risk of local recurrence (Figure 4.2).
The risk of local recurrence for all solid malignancies is clearly increased if negative margins are not achieved. The adequacy of the negative margin has been defined for most tumor types either from retrospective clinical experience or prospective clinical trials. For example, a 5-cm margin is an adequate bowel margin for primary colon cancers that has been established from clinical experience. Likewise, it is accepted that a 2-cm distal margin for rectal cancers results
in adequate local control. Through several prospective, randomized clinical trials, the margins of excision for primary cutaneous melanomas differ according to the thickness of the primary (see Chapter 60). It was a commonly held notion that the development of a local recurrence would in itself result in metastatic disease with decreased overall survival. However, this has not been borne out in the context of prospective trials as described here.
The emergence of multimodal therapy has dramatically affected the surgical approach to many primary cancers, especially when surgical resection of the tumor is combined with radiotherapy. Local control is significantly improved after surgical resection of breast, rectal, sarcoma, head and neck, and pancreatic primary cancers. In fact, the addition of radiation therapy as an adjunctive therapy has allowed for less-radical procedures to be performed with an improvement in the quality of life of patients. A prime example of this is in breast cancer. Several clinical trials have demonstrated that the overall survival of patients with invasive breast cancer was comparable if treated by mastectomy versus lumpectomy plus adjuvant radiotherapy (see Chapter 55). This realization has resulted in better cosmesis and quality of life. In the National Surgical Adjuvant Breast and Bowel Project protocol, B-06, local recurrence in breast cancer patients did not affect overall survival.12 In this seminal study, women with stage I or II breast cancer were randomized to total mastectomy with axillary node dissection, lumpectomy, and axillary node dissection followed by breast irradiation, or lumpectomy and axillary node dissection without irradiation. There was a significantly greater local relapse of tumor in women who underwent lumpectomy who did not receive breast irradiation versus those who received it (10% versus 39%, respectively, P less than 0.001). However, there was no difference in overall survival between any of the randomized groups. This study demonstrated the improved local control achieved with irradiation combined with lumpectomy.
Another example of how irradiation has altered surgical management of cancers is with extremity sarcomas. Before the 1970s, amputation was the standard surgical therapy of extremity soft tissue sarcomas because of the excessive local relapse rate with wide excisions. In a landmark trial conducted at the National Cancer Institute, subjects with high-grade soft tissue sarcomas were randomized to receive amputation versus limb-sparing surgery plus radiotherapy.13 All subjects received postoperative chemotherapy. Despite a higher local recurrence rate in the limb salvage group, there were no significant differences in overall survival between the randomized groups. This study paved the way for offering limb salvage procedures for patients with soft tissue sarcomas.
As the field of multimodality therapy has developed, the role of surgery as primary therapy for certain solid malignancies has changed. The concept of neoadjuvant therapy where chemotherapy and/or radiation therapy is administered before surgical resection has become standard care for some tumors. A prime example of this is the treatment of anal squamous cell cancers. Before the 1970s, the primary therapy for this cancer was an abdominoperineal resection, which involves removal of the rectum and creation of a permanent colostomy. The discovery of effective chemoradiation therapy for this tumor has resulted in a high percentage of complete responses in many patients who then require having only excisional biopsies of residual scar.14,15 This change has spared patients from having an abdominoperineal resection, which is now reserved for those who fail to completely respond to chemoradiation or who subsequently relapse. Another example is the treatment of childhood rhabdomyosarcomas. In breast cancer, the use of neoadjuvant chemotherapy has been able to render many more women to be candidates for breast-sparing surgery who may not have been initially because of large tumor size.16,17 Postoperative adjuvant therapies involving chemotherapy and/or radiation therapy have also become standard approaches in many solid tumors, resulting in improved local control and overall survival.
Was this article helpful?
Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.