Subclinical disease

Abstract

A number of patients with cancer later develop metastases in the draining lymphatics, which initially were clinically negative. These occult deposits represent subclinical disease in lymphatic areas accessible to palpation, like the neck, axillae, and groin. The concept applies also to the microscopic disease left in an area after a surgical procedure is known to have removed all gross cancer, yet some patients later develop a recurrence. The term “subclinical disease” refers only to disease in a specific anatomic area, based on clinical facts. Radiobiological parameters account for the fact that subclinical disease requires less irradiation to be eradicated than gross cancer. The concept has two main applications, elective irradiation of clinically negative peripheral lymphatics and locoregional irradiation combined with surgery, which are determined by site and disease. The concept of subclinical disease also has implications for chemotherapy, which bear a direct relationship between chemotherapy both with radiation therapy and surgery. Cancer 53:1274‐1284, 1984.

The Role of Intraoperative Radiation Therapy (IORT) in the Treatment of Locally Advanced Gynecologic Malignancies

“…Patients whose pelvic lymph nodes were unresectable exhibited a relapse-free survival of 0% and a pelvic failure rate of 56% [15]. Unfortunately, the control rate mediated by EBRT alone in the setting of grossly involved pelvic lymph nodes is in the order of 50% [16]. Long-term survival among cervical cancer patients with positive para-aortic lymph nodes (microscopic or limited-volume) is reported to be 25%-50% [17,18].…”

Debulking metastatic pelvic nodes before radiotherapy in cervical cancer patients: a long-term follow-up result

“…Tumor cells thriving in a relative hypoxic post-surgical field are more radio-resistant and surgical debulking of metastatic nodes may therefore have a negative influence on the radiotherapy response [6]. The high pelvic control rate after radiotherapy in our series did not suggest that this is a major problem.…”

“…Studies have shown that the response to radiotherapy treatment is inversely related to the size of the tumor and that the relationship between dosage and size is logarithmic [4][5][6]. Standard pelvic radiotherapy is effective in eradicating most subclinical metastatic nodes but those with bulky pelvic nodes are at a substantial risk of developing pelvic failure [7,8].…”

The Management of Adenocarcinoma of the Rectum

“…As most patients have locally advanced disease, they undergo a protracted course of preoperative radiotherapy, in which they receive 5400 cGy (a four-field technique of 4500 cGy in 25 fractions, plus a 900 cGy posterior three-field boost in five fractions) over a time period of six weeks. 19 They then have a four to six-week "rest" time before proceeding to surgery. If patients have small (less than 4 cm in diameter), mobile, mid or lower third rectal tumors, a shorter course of radiotherapy is used.…”