Chemo Before Chemoradiation Boosts Cervical Cancer Outcomes

Platinum-based chemotherapy, given before chemoradiation, improved outcomes for patients with advanced cervical cancer.

Patients with locally advanced cervical cancer saw an improvement in survival when they added platinum-based chemotherapy before chemoradiation, compared to those who had chemoradiation alone, according to findings from the phase 3 INTERLACE clinical trial.

Findings, which were presented at the 2023 ESMO Congress, showed that induction (given before the main treatment to shrink cancer) chemotherapy followed by chemoradiation reduced the risk of progression or death by 35% vs chemoradiation alone. Patients treated in the experimental arm (250 patients) experienced three- and five-year progression-free survival (PFS; time from treatment until disease progression or death) rates of 75% and 73%, respectively. Those rates were 72% and 64%, respectively, for patients given chemoradiation alone (250 patients).

Furthermore, induction chemotherapy prior to chemoradiation reduced the risk of death by 39% vs chemoradiation alone. Patients in the experimental arm achieved three- and five-year overall survival (OS; time from treatment until death of any cause) rates of 86% and 80%, respectively, vs 80% and 72%, respectively, for those given chemoradiation alone.

“Induction chemotherapy with weekly paclitaxel and carboplatin delivered immediately before chemoradiation should be considered the new standard in locally advanced cervical cancer and is feasible across diverse health care settings,” lead study author Mary McCormack, of University College London in the United Kingdom, said in a presentation of the data.

For more than 20 years, chemoradiation has served as the standard of care for patients with locally advanced cervical cancer; however, up to 30% of patients still relapse and die from metastatic disease.

INTERLACE enrolled newly diagnosed patients with stage IB1 (node positive), 1B2, 2, 3B or 4A squamous, adeno, or adenosquamous cervical cancer. Patients needed to be fit for chemotherapy and radical radiotherapy and have adequate renal, liver and bone marrow function.

Patients were not allowed to have nodes above aortic bifurcation on imaging and prior pelvic radiation was not permitted.

Investigators randomly assigned patients to receive induction chemotherapy followed by chemoradiation or chemoradiation alone. In the experimental arm, patients received induction therapy once per week for six weeks before beginning chemoradiation in week 7. In both arms, chemoradiation consisted of 40 mg/m2 of cisplatin once every week for five weeks plus external beam radiation (EBRT) ranging from 40 Gy to 50.4 Gy given in 20 to 28 fractions. Patients also received brachytherapy at a minimum total of biologically equivalent doses of 78 Gy. It was recommended that patients receive image-guided adaptive brachytherapy.

The overall treatment time of chemoradiation was not to exceed 50 days and all participating centers were required to undergo radiotherapy quality assurance.

Patients were stratified by site; stage; nodal status; 3D-conformal vs intensity-modulated radiotherapy (IMRT); 2D vs 3D brachytherapy; tumor size; and squamous cell carcinoma vs other.

PFS and OS served as the trial’s co-primary end points. Key secondary end points included side effects, pattern of relapse, quality of life and time to subsequent treatment.

Baseline characteristics showed that the median age was 46 years (range, 26-78) in the experimental arm and 46 years (range, 24-78) in the control arm. The majority of patients had an ECOG performance status of 0, meaning that they could perform all of their daily tasks with no assistance (86% and 88% for the experimental and control arms, respectively), were from the United Kingdom (76% and 76%), had FIGO (2008) stage 2B disease (71% and 70%), had squamous histology (82% and 82%) and were node negative (58% and 57%). The median longest tumor diameter was 4.8 cm (range, 1.3-13.5) and 4.9 cm (range, 1.8-12.8), respectively.

In the experimental arm, 84% of patients completed six cycles of induction chemotherapy and 92% completed at least five cycles. The primary reasons for receiving less than six cycles were side effects (11%; 29 patients), including blood-related side effects (nine patients), non-hematologic side effects (17 patients) and both (three patients); and patient withdrawal or other (4%; 10 patients). The median interval between induction chemotherapy and radiotherapy was seven days (range, 5-53).

During chemoradiation, 68% of patients in the experimental arm completed all five cycles of cisplatin and 85% completed at least four cycles. Those rates were 79% and 90%, respectively, in the control arm. In the experimental arm, the primary reasons for receiving less than five cycles of cisplatin were side effects leading to discontinuation (27%), including hematologic side effects (34 patients), non-hematologic side effects (20 patient) and both (14 patients); and other (5%). For the chemoradiation alone arm, the main reasons for not completing five cycles of cisplatin were side effects leading to discontinuation (13%), including hematologic side effects (four patients), non-hematologic side effects (25 patients) or both (four patients); and other (8%).

Ninety-seven percent of patients in the experimental arm and 92% of patients in the control arm received EBRT. In the experimental arm, the rates of IMRT and 3D-conformal radiation were 42% and 58%, respectively; those rates were 40% and 60%, respectively, for the control arm. The majority of patients in the experimental arm (98%) and control arm (97%) received brachytherapy consisting of 2D point A (19% and 22% for the experimental and control arms, respectively), 3D point A (51% and 48%) and 3D HRCTV D90 (30% and 30%).

“Adherence to standard chemoradiation was high in both arms and reflected best clinical practice,” McCormack noted.

The median overall treatment time was 45 days (range, 36-70) in the experimental arm and 45 days (range, 37-88) in the control arm.

In the induction chemotherapy/chemoradiation arm, the rates of total local/pelvic relapses and total distant relapses were 16% and 12%, respectively; 10% of patients had local/pelvic relapses, 6% had distant relapses and 6% had both local/pelvic and distant relapses. In the chemoradiation alone arm, the rates of total local/pelvic relapses and total distant relapses were 16% and 20%, respectively; 8% of patients had local/pelvic relapses, 12% had distant relapses and 8% had both.

Regarding safety, any-grade side effects occurred in 99% of patients in the induction chemotherapy/chemoradiation arm and 95% of patients in the chemoradiation arm. The rates of grade 3/4 side effects were 59% and 48%, respectively.

Any-grade hematologic side effects were reported in 30% of patients in the experimental arm and 13% of patients in the control arm. The most common any-grade hematologic side effect included neutropenia (19% and 5% for the experimental and control arms, respectively), anemia (5% and 4%) and thrombocytopenia (5% and 2%). The rates of any-grade non-hematologic side effects were 44% and 43%, respectively, and the most common included abdominal/pelvic pain (5% and 7%); diarrhea (8% and 12%); fatigue, muscle weakness, or joint pain (11% and 6%); and infection (6% and 5%).

“As anticipated, hematologic toxicity was greater in the experimental arm, but this did not compromise the delivery of chemotherapy,” McCormack concluded.

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