AT THE GENITOURINARY CANCERS SYMPOSIUM

ORLANDO (FRONTLINE MEDICAL NEWS) – Although two cycles of bleomycin-etoposide-cisplatin (BEP) chemotherapy typically comprise adjuvant treatment for nonseminomatous or combined germ cell testicular cancer, investigators suggest one cycle may be sufficient.

“Over recent years, evidence has begun to accumulate that one single cycle of BEP may be sufficient to reduce the recurrence rate to below 5%,” said Robert Anthony Huddart , MBBS, MRCP, FRCR, PhD, of the Institute of Cancer Research in Sutton, England. “If this is confirmed, it means we could have a similar cure rate to two cycles of lower-dose BEP and that would reduce the overall burden of chemotherapy and health care resource usage.”

Dr. Huddart and his coauthors assessed 246 people from 33 centers in the United Kingdom. The patients had stage I nonseminomatous or combined germ cell testicular cancer. Instead of the standard two cycles of lower-dose etoposide regimen, BE360P post orchidectomy, the investigators administered one dose of BE500P and then followed patients for a mean 39 months.

The primary endpoint of the single-arm study was malignant recurrence at 2 years. Some patients will recur with acute, undifferentiated disease at multiple sites, often with rising markers; the treatment for these patients is further chemotherapy, Dr. Huddart explained. In contrast, other patients present with differentiated teratomas, usually in the peritoneum; they tend to be marker negative and candidates for surgical resection.

Malignant recurrence rate

“The headline result for the study is … we had three malignant recurrences, for a 1.3% rate, with an upper confidence limit of 4% – below our 5% target,” Dr. Huddart said at the 2017 Genitourinary Cancers Symposium sponsored by the American Society of Clinical Oncology, ASTRO, and the Society of Urologic Oncology. “We also had three patients – or 1.3% – who presented with differential teratoma[s], so the overall event rate was 2.6% at 2 years.”

“This adjuvant chemotherapy is highly successful in reducing recurrence, with a 2-year recurrence-free rate of 98%. And it does avoid the need for intensive surveillance,” Dr. Huddart said.

“This paper demonstrates that single-cycle treatment is safe and effective and two cycles are unnecessary,” said study discussant Noel W. Clarke , MBBS, FRCS, of the Christie Hospital NHS Foundation Trust in Manchester, England. “So why don’t we give all patients this kind of treatment? It doesn’t come without toxicity,” he said.

Adverse events

Myelosuppression comprised the majority of grade 3 and 4 acute toxicities in the study, which “is what you would expect with BEP chemotherapy,” Dr. Huddart said. The most common adverse events were neutropenia, leukopenia, and febrile neutropenia. He pointed out that the febrile neutropenia rate “was a low 6.4%.” A total of 104 patients experienced any toxicity.

A meeting attendee asked why the investigators did not consider a lower dose of etoposide in the study. Dr. Huddart replied, “We used a standard dose BEP because etoposide reduction might reduce the toxicity, but it might also reduce the efficacy.”

In terms of overall survival, three participants died during the study. One presented 6 months after adjuvant chemotherapy with a large, intra-abdominal recurrence; another patient died from a secondary primary lung cancer; and the third from a drug overdose.

In addition to the 2-year primary outcomes, by 4 years, another malignancy recurrence occurred, for a cumulative rate of 1.8%; including teratomas, the all-recurrence rate increased to 3.1%. “Therefore, we can successfully demonstrate the rate of malignancy after one cycle of BEP is less than 5%,” Dr. Huddart said.

Participants were aged 16 years and older with clinical stage I disease, including both mixed or pure nonseminomatous germ cell tumors. Patients also received two prophylactic agents. “We were keen to reduce the incidence of neutropenic sepsis and gave propped up G-CSF [granulocyte-colony stimulating factor] and propped up antibiotics,” Dr. Huddart said.

“This is a new treatment approach for an uncommon cancer,” Dr. Huddart said. Adoption of the protocol would reduce the overall exposure to chemotherapy in a young patient population, he added. “Just 20% of patients were [older than] age 40.”

op@frontlinemedcom.com

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