The use of radiotherapy for patients with low rectal cancer: an overview of the Lyon experience

Retrospective study of preoperative chemoradiotherapy with capecitabine versus capecitabine plus oxaliplatin for locally advanced rectal cancer

This study aimed to evaluate whether the addition of oxaliplatin to a neoadjuvant chemoradiotherapy (CRT) regimen could improve survival benefit in locally advanced rectal cancer (LARC) patients. We retrospectively analysed 73 LARC patients (cT2-4 and/or cN1-2) who received preoperative CRT with capecitabine followed by surgery (arm A, 43 patients) or capecitabine plus oxaliplatin followed by surgery (arm B, 30 patients). The main endpoints of the study were pathologic complete response (pCR) rate, overall survival (OS) and disease-free survival (DFS). The secondary endpoints included the sphincter preservation rate and safety. The pCR for arms A and B were 28% and 17% (P = 0.267). In arms A and B, the mean OS was 84.287 months (95% CI 68.413-100.160) and 106.333 months (95% CI 99.281-113.386) (P = 0.185); the mean DFS was 72.812 months (95% CI 56.271-89.353) and 95.073 months (95% CI 83.392-106.754) (P = 0.310); and the sphincter preservation rates were 72% and 67%, respectively (P = 0.619). The incidence of grade 3 toxicity was much higher in arm B than in arm A (57% vs. 21%, P = 0.002). Adding oxaliplatin to a preoperative CRT regimen for LARC did not improve the survival benefits of patients or increase toxicity.

Physics aspects of the Papillon technique-Five decades later

PURPOSE

The Papillon technique using 50-kVp soft X-rays to treat rectal adenocarcinomas was developed and clinically implemented in the 1960s. We describe differences between accurate dosimetry and clinical implementation of this technique that is extending from its very inception to date.

METHODS AND MATERIALS

A renaissance of the Papillon technique occurred with two recently introduced 50-kVp systems: Papillon+ by Ariane and a custom-made rectal applicator (consisting of a surface applicator inserted into a proctoscope) by iCAD's Xoft Axxent Electronic Brachytherapy (eBT) System (iCad, Inc., Sunnyvale, CA). In contrast to the initial design, we investigated the impact of introducing a plastic lid, which would provide more reproducible and more accurate dose delivery across the rectal adenocarcinoma patient population. We use both parallel-plate chamber and radiochromic film dosimeters to determine differences in basic dosimetry characteristics (beam half-value layers, outputs, percent depth doses, and profiles) between the Xoft Electronic Brachytherapy rectal applicator system with and without the plastic lid in place.

RESULTS

Compared to the open-cone applicator, the proposed applicator with the plastic lid produces a slightly harder (more penetrating) beam quality (half-value layer of 1.4 vs. 1.3-mm Al), but with reduced output (by 33%), and a slightly broader beam with flatness not worse than 3% and symmetry not worse than 2%.

CONCLUSIONS

In addition to characterizing beam properties modified by the possible introduction of the plastic cap, we also pointed out and addressed misconceptions in the use of radiochromic films for dose measurements at low-energy photon beams.

Capecitabine and oxaliplatin in the preoperative multimodality treatment of rectal cancer: surgical end points from National Surgical Adjuvant Breast and Bowel Project trial R-04

PURPOSE

The optimal chemotherapy regimen administered concurrently with preoperative radiation therapy (RT) for patients with rectal cancer is unknown. National Surgical Adjuvant Breast and Bowel Project trial R-04 compared four chemotherapy regimens administered concomitantly with RT.

PATIENTS AND METHODS

Patients with clinical stage II or III rectal cancer who were undergoing preoperative RT (45 Gy in 25 fractions over 5 weeks plus a boost of 5.4 Gy to 10.8 Gy in three to six daily fractions) were randomly assigned to one of the following chemotherapy regimens: continuous intravenous infusional fluorouracil (CVI FU; 225 mg/m(2), 5 days per week), with or without intravenous oxaliplatin (50 mg/m(2) once per week for 5 weeks) or oral capecitabine (825 mg/m(2) twice per day, 5 days per week), with or without oxaliplatin (50 mg/m(2) once per week for 5 weeks). Before random assignment, the surgeon indicated whether the patient was eligible for sphincter-sparing surgery based on clinical staging. The surgical end points were complete pathologic response (pCR), sphincter-sparing surgery, and surgical downstaging (conversion to sphincter-sparing surgery).

RESULTS

From September 2004 to August 2010, 1,608 patients were randomly assigned. No significant differences in the rates of pCR, sphincter-sparing surgery, or surgical downstaging were identified between the CVI FU and capecitabine regimens or between the two regimens with or without oxaliplatin. Patients treated with oxaliplatin experienced significantly more grade 3 or 4 diarrhea (P < .001).

CONCLUSION

Administering capecitabine with preoperative RT achieved similar rates of pCR, sphincter-sparing surgery, and surgical downstaging compared with CVI FU. Adding oxaliplatin did not improve surgical outcomes but added significant toxicity. The definitive analysis of local tumor control, disease-free survival, and overall survival will be performed when the protocol-specified number of events has occurred.

Future directions in neoadjuvant therapy of rectal cancer: maximizing pathological complete response rates

Neoadjuvant therapy is widely accepted as the current standard of care for localized rectal cancer. Downstaging of disease has been significantly improved and pathological complete response rates (pCR) which were historically below 10% with preoperative radiation alone, now range from 15% to 30% with preoperative chemo-radiation. While the availability of new chemotherapeutic drugs (Irinotecan, Oxaliplatin, etc.) and molecular targeted agents (Bevacizamab, Cetuximab, etc.) hold a great deal of promise, results of recent studies indicate that the pCR rate with neoadjuvant therapy appears to have plateaued at 20-30%. The use of more intensive multidrug combinations has, however, significantly increased the toxicity of treatment. New paradigms in neoadjuvant therapy are therefore needed to further improve results of treatment. This review presents strategies for neoadjuvant therapy, with the potential to improve pCR rates and also survival of patients.

Complete clinical response after preoperative chemoradiation in rectal cancer: is a "wait and see" policy justified?

PURPOSE

A proportion of patients, who receive preoperative chemoradiation for locally advanced (T3, T4, NX) rectal cancer achieve a complete clinical response and a pathologic complete response in the region of 15 to 30 percent. Support is growing in the United Kingdom for the concept of "waiting to see" and not proceeding to radical surgery when a complete clinical response is observed. The purpose of this review was to use a literature search to assess how often complete clinical response is achieved after neoadjuvant chemoradiation, the concordance of this finding with pathologic complete response, and to determine whether it is feasible to observe patients who achieve complete clinical response rather than proceed to surgery.

RESULTS

In total, 218 Phase I/II or retrospective studies and 28 Phase III trials of preoperative radiotherapy or chemoradiation were identified: 96 percent of trials documented the pathologic complete response, but only 38 trials presented data on the achievement of a complete clinical response/partial clinical response. Only five studies were found in which patients with clinically staged T2/T3 tumors were treated with radiotherapy/chemoradiation and did not routinely proceed to surgery and also reported on the long-term outcome of a "wait and see" policy.

DISCUSSION

It remains uncertain whether the degree of response to chemoradiation in terms of complete clinical response or pathologic complete response is a useful clinical end point. Studies that include T3 rectal cancer are associated with high local recurrence rates after nonsurgical treatment. Few studies report long-term outcome after achievement of a complete clinical response.

CONCLUSIONS

The end point of complete clinical response is inconsistently defined and seems insufficiently robust with only partial concordance with pathologic complete response. The rationale of a "wait and see" policy when complete clinical response status is achieved relies on retrospective observations, which are currently insufficient to support this policy except in patients who are recognized to be unfit for or refuse radical surgery.

Rectal cancer: changing patterns of referral for radiation therapy 1982-1997

BACKGROUND

The purpose of the present study was to evaluate the changing role of radiation therapy in rectal cancer and to determine the patterns of referral of patients during a 15-year period.

METHODS

From 1982 to 1997, 464 patients with carcinoma of the rectum were referred to the Department of Radiation Oncology, Royal Prince Alfred Hospital: 79% of patients had locoregional disease alone and 21% had distant metastasis. Radiation therapy consisted of irradiation (definitive or palliative) alone to the primary tumour in 9.7% of cases; preoperative radiation in 7.3% of cases: preoperative chemoradiation in 7.5% of patients: postoperative radiation in 15.3% of patients: postoperative chemoradiation in 12.31% of patients: treatment of pelvic recurrence in 23.5% of patients and treatment of metastases in 9.1% of patients. The remainder were treated elsewhere (1.9%) or not treated (13.4%).

RESULTS

There was an average annual 14% increase in referrals over the accrual period. Recurrent rectal cancer decreased from approximately 30% of referrals during 1982-91 to approximately 10% in 1995-7. The use of postoperative adjuvant radiation reached a peak of 50% in 1993. The use of preoperative radiation increased suddenly in 1994 from < 10% to a sustained rate of approximately 30% of referrals. The use of chemoradiation commenced in 1990 for postoperative adjuvant treatment and in 1994 for preoperative treatment. The median survival time from initial diagnosis was 35 months, with 2- and 5-year survival rates of 62 and 28%, respectively. Survivals at 5 years for patients treated with preoperative and postoperative radiation (with or without chemotherapy) and with recurrent disease were 56, 44 and 21%, respectively.

CONCLUSIONS

The present study illustrates the changing role of radiation therapy in the management of rectal cancer. The increase in referrals over the observation period was due to increased multidisciplinary input into the initial management of these patients, based on reported clinical trials. The steady increase in the use of adjuvant therapy has paralleled a decrease in referrals for treatment of recurrence and reflects current clinical results. The sequencing of adjuvant therapy is changing currently, with greater emphasis on preoperative adjuvant treatment. Currently most adjuvant therapy includes chemotherapy.

Endocavitary irradiation for early rectal carcinomas T1 (T2). A series of 101 patients treated with the Papillon's technique

PURPOSE

This work is a retrospective analysis of a series of patients treated with endocavitary irradiation stressing the role of transrectal ultrasound (TRUS), which has been used routinely in the staging since 1987.

METHODS AND MATERIALS

Between 1977 and 1993, 101 patients with infiltrating adenocarcinomas were treated. Clinical staging was 65 T1 N0 and 36 T2 N0. TRUS used in 36 patients showed: 22 UT1 N0, 10 UT2 N0, and 3 UT2 N1. Contact x-ray was delivered with a 50 kV radiotherapy unit. The median dose was 92 Gy (60-125) in five fractions, 55 days. In 28 patients a boost was given with 192Ir implant delivering a median dose of 25 Gy/21 h.

RESULTS

Complete response was observed in all patients at the completion of treatment. Loco-regional failures were seen in 14 patients (local in 7 patients, nodal pararectal in 6 patients, and local + nodal in 1 patient). A curative salvage treatment was attempted in 13 patients and resulted in an ultimate pelvic control rate of 99 patients. Rectal preservation was possible in 92 patients. Overall and specific 5-year survival was 83.3% and 94.4%. No serious complication was observed. TRUS was more sensitive than digital rectal examination to detect involvement of pararectal metastatic nodes (N1). No loco- regional relapse was observed out of 22 UT1 N0.

CONCLUSION

Endocavitary irradiation can cure early adenocarcinoma of the rectum without complication. TRUS appears as a significant improvement in the selection of patients amenable to this treatment. If restricted to UT1 N0 tumors, endocavitary irradiation should control locally more than 90% of these patients. Any UN1 is a contraindication for endocavitary irradiation alone.

Combined curative radiation therapy alone in (T1) T2-3 rectal adenocarcinoma: a pilot study of 29 patients

AIM

Analysis of a pilot study including 29 consecutive patients with high surgical risk or refusal of colostomy treated with radiation therapy alone with curative intent.

PATIENTS

Between 1986 and 1992, 29 patients were treated for infiltrating adenocarcinoma of the rectum. Median age was 72 years. Transrectal ultrasound staging was used in 24 patients (T1, 2; T2, 14; T3, 13; N0, 23; N1, 6). In 20 patients the lower border of the tumor was at 5 cm or less from the anal verge and in 19 patients the diameter exceeded 3 cm. CEA was elevated in seven cases.

TREATMENT

Contact X-ray (50 kV) was given first (70 Gy/3 fractions). External beam radiation therapy used a three-field technique in the prone position. Accelerated schedule (39 Gy/13 fractions/17 days) with a concomitant boost "field within the field' (4 Gy/4 fractions). Six weeks later an iridium-192 implant was performed in 21 (20 Gy/22 h).

RESULTS

Median follow-up time was 46 months. Overall and specific survival at 5 years was 68% (SE = 0.09) and 76% (SE = 0.08). Local control was obtained in 21/29 patients (72%). There was one grade 2 rectal bleeding and five grade 2 rectal necroses. The overall tolerance was good in these frail patients.

DISCUSSION

For T2. T3 or T1 > 3 cm diameter rectal adenocarcinoma, where contact X-ray alone is not recommended, a combined treatment with radiation therapy alone is able to give good local control with acceptable toxicity. This treatment should be restricted to inoperable patients.